MFC r228808, r228847, 229395:

MFC r228808, r228847, 229395:

r228808, r228847:
Make cd driver to handle Audio CDs, reporting their 2352 bytes sectors to
GEOM and using READ CD command for reading data, same as acd driver does.
Audio CDs identified by checking respective bit of the control field of
the first track in TOC.

229395:
Add support for CDRIOCGETBLOCKSIZE and CDRIOCSETBLOCKSIZE IOCTLs to control
sector size same as acd driver does. Together with r228808 and r228847 this
allows existing multimedia/vlc to play Audio CDs via CAM cd driver.

PR:		ports/162190
Sponsored by:	iXsystems, Inc.

git-svn-id: svn://svn.freebsd.org/base/stable/8@230015 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f